Standardise group options button and refactor icon-button helper

This refactor makes this helper more general and easier to use.

You now can pass it:
- a data method for a delete button
- more classes for changing its color
- data-toggle for making it a dropdown

Added options cog icon to make the group options dropdown a standardized app button
![screen shot 2013-07-04 at 12 51 26 pm](https://f.cloud.github.com/assets/1380820/746978/32213458-e443-11e2-9b5d-0f10744b01b0.png)
![screen shot 2013-07-04 at 12 56 51 pm](https://f.cloud.github.com/assets/1380820/746996/e55f749e-e443-11e2-9864-f965078d3a1b.png)